I guess the spawnkilling issue is almost resolved nowadays. The principle is very simple: if you are under spawn protection, you shouldn't be attacked, and it is punishable. Otherwise you can be attacked and killed without any restrictions.
But, again, I would improve it a bit as I said
here. I have already faced a situation when our opponents ran to civilian spawn and camped there while being protected by their invulnerable civilian friends. Besides, when we accidentally hit them, the popup window appeared, stunning us. So, the spawn protection must be lifted either if player leaves his spawning zone, or starts to shoot anyone, or specified amount of time passes.
As for expanding spawning zones, I agree that it is needed,
+1. Also they must be defined and shown on the minimap for each class spawn.